The present invention relates to sugar centrifugals preferably for the continuous separation of low-viscosity, low-grade sugar massecuites into sugar and runoff. Such centrifugals are generally equipped with a conically shaped basket tapering outwardly in an upward direction and rotating about a vertical axis, with a massecuite distributing device comprising a rotating accelerating cup and a rotating massecuite distributing bell tapering outwardly in a downward direction over the cup. In the sugar industry, it is a basic aim to produce as much sugar as possible from sugar beets and/or from sugar cane. Achieving this aim, however, is not always possible, because, for example, the consistencies of the massecuites to be centrifuged vary considerably. Such variations are most evident when low-grade massecuite is being centrifuged. Hitherto, sugar factories have been compelled to adapt their massecuites to the centrifugals, particularly where low-viscosity, low-grade massecuites are produced, depending on the process applied, in order to obtain a good quality after product sugar having uniform crystals.
Continuously operating centrifugals in which low-grade massecuites may also be centrifuged and in which a distributing bell is incorporated are known. According to U.S. Pat. No. 3,837,913 corresponding to German patent publication No. 2,207,663, the distributing bell has the task of transferring the massecuite as uniformly as possible to the basket so as to ensure a smooth run of the centrifugal. A continuously operating centrifugal operates efficiently only if massecuites having a substantially uniform consistency are being centrifuged. Massecuites having a low liquid content reduce the throughput efficiency due to the poor distribution on the screen of the centrifugal basket. The sugar produced from low viscosity massecuites may have a poor quality although the throughput remains the same, since the high syrup liquid content makes the massecuite slide too rapidly over the working screen without the whole of the runoff being extracted. To prevent this, the throughput must be reduced.
According to German utility model application No. 1,782,182, the main dewatering of the massecuite is to take place through the bottommost screen zone. In this respect the statements made in connection with DE-AS No. 2,207,663, (U.S. Pat. No. 3,837,913) apply, i.e., too large a quantity of runoff is separated in the case of high viscosity massecuites, with the result that the massecuite distribution on the working screen of the basket is not uniform, whereby an uneven run of the centrifugal results so that the throughput must be reduced until the centrifugal runs smoothly again. On the other hand, if the massecuite is of low viscosity, the dewatering will be insufficient. The quality of the produced sugar is poor and the throughput must practically be reduced.